package com.jiang.专题.队列.Q0304;

import java.util.Stack;

/**
 * @author Jiang
 * @version 1.0
 * @date 2025/03/03 1:47
 */
class MyQueue {
    Stack<Integer> s1;
    Stack<Integer> s2;

    /** Initialize your data structure here. */
    public MyQueue() {
        s1 = new Stack<>();
        s2 = new Stack<>();
    }

    /** Push element x to the back of queue. */
    public void push(int x) {
        s1.push(x);
    }

    /** Removes the element from in front of queue and returns that element. */
    public int pop() {
        if (s2.isEmpty()) s1Tos2();
        return s2.pop();
    }

    /** Get the front element. */
    public int peek() {
        if (s2.isEmpty()) s1Tos2();
        return s2.peek();
    }

    /** Returns whether the queue is empty. */
    public boolean empty() {
        return s1.isEmpty() && s2.isEmpty();
    }

    private void s1Tos2() {
        while(!s1.isEmpty()) {
            s2.push(s1.pop());
        }
    }
}

/**
 * Your MyQueue object will be instantiated and called as such:
 * MyQueue obj = new MyQueue();
 * obj.push(x);
 * int param_2 = obj.pop();
 * int param_3 = obj.peek();
 * boolean param_4 = obj.empty();
 */
